An apparatus described in Patent Document 1, for example, is conventionally known as one such control apparatus for a vehicle. Generally, in conventional vehicles including those employing the technique of Patent Document 1, auxiliary devices such as a compressor for an air conditioner and an alternator are driven by the output of an internal combustion engine. If an auxiliary device is in operation when the output of the engine is low, such as when the engine is idling, the load caused by the auxiliary device is increased and operation of the engine is destabilized. To solve this problem, the conventional control apparatus performs output increasing control, or, in other words, idle-up control, to increase the output of the engine when the auxiliary device is operated. The output of the engine is thus increased when the auxiliary device is in operation compared to when the auxiliary device is not in operation. This restricts destabilization of the operation of the engine caused by the operating auxiliary device.